128521117 has 2 divisors, whose sum is σ = 128521118. Its totient is φ = 128521116.

The previous prime is 128521103. The next prime is 128521177. The reversal of 128521117 is 711125821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76983076 + 51538041 = 8774^2 + 7179^2 .

It is a cyclic number.

It is not a de Polignac number, because 128521117 - 2¹⁹ = 127996829 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128521177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64260558 + 64260559.

It is an arithmetic number, because the mean of its divisors is an integer number (64260559).

Almost surely, 2^128521117 is an apocalyptic number.

It is an amenable number.

128521117 is a deficient number, since it is larger than the sum of its proper divisors (1).

128521117 is an equidigital number, since it uses as much as digits as its factorization.

128521117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1120, while the sum is 28.

The square root of 128521117 is about 11336.7154414319. The cubic root of 128521117 is about 504.6514171221.

Adding to 128521117 its reverse (711125821), we get a palindrome (839646938).

The spelling of 128521117 in words is "one hundred twenty-eight million, five hundred twenty-one thousand, one hundred seventeen".